Headlight warning system

ABSTRACT

A headlight warning system controlled from the fuse block of a vehicle which is connected to the vehicle and powered from the headlight switch controlled dimmer switch to produce an audible warning signal when the headlight switch is closed and the ignition switch is open. The system uses a transistor with its base connected to the fuse block and its emitter connected to the dimmer switch, and a buzzer unit responsive to conduction of the transistor to generate an audible warning signal.

United States Patent Lee [54] HEADLIGHT WARNING SYSTEM [76] Inventor:Maw-Huei Lee, 25l Tenth St.,

N,W.. Apt 250, Bldg, 8, Atlanta, Ga. 303 l 8 221 Filed; Apr. 27, 1973211 Appl.No,:3S4,934

[52] US. Cl 340/52 D; 337/50 R; 337/75 A; 337/258 F [5|] Int. Cl H B60q1/00 [58] Field of Search 340/52 R, 52 D, 74, 248, 340/256; 339/258 F,50 R, 95 A, 257

[56] References Cited UNITED STATES PATENTS 3,275,736 9/1966 Hotine eral. 339/95 A 3,283,299 ll/l966 Savino 340/52 D 3,328,577 6/1967 Piste ctal H 339/50 R 51 Sept. 9, 1975 3,478,307 11/1969 Testo 339/258 F3,622,954 ll/l97l Hovnanian et a]. 339/95 A 3,649,960 3/l972 Severn340/52 D Primary ExaminerMarshall M. Curtis Attorney, Agent, or Firm-B.J, Powell l 5 ABSTRACT A headlight warning system controlled from thefuse block of a vehicle which is connected to the vehicle and poweredfrom the headlight switch controlled dimmer switch to produce an audiblewarning signal when the headlight switch is closed and the ignitionswitch is open. The system uses a transistor with its base connected tothe fuse block and its emitter connected to the dimmer switch, and abuzzer unit responsive to conduction of the transistor to generate anaudible warning signal.

4 Claims, 6 Drawing Figures PATENTEU 1975 sum 2 u{ 2 HEADLIGHT WARNINGSYSTEM BACKGROUND OF THE INVENTION Many times drivers inadvertentlyleave their automobile headlights switched on when they leave thevehicle. Because the headlights are connected directly to the batteryindependently of the ignition switch. the power in the battery isexpended if the automobile is unattended for any substantial period oftime. This causes the driver to be unable to start the vehicle upon hisreturn thereby necessitating expenses in starting the vehicle from anoutside power source and recharging the battery. Some automotivemanufacturers are adding an automatic headlight switch circuit whichdisables the headlights a predetermined period of time after theignition switch has been turned off. however. such circuits arerelatively expensive and are available on only a relatively fewvehicles. While a few separately manufactured warning systems areavailable. the location and arrangement of the circuits in the vehiclemakes it very difficult to install such a headlight warning system oncethe original manufacture of the vehicle is complete.

SUMMARY OF THE INVENTION These and other problems and disadvantages areovercome by the invention disclosed herein by providing an alarm whichnotifies the driver of a vehicle when the headlight are inadvertentlyswitched on. which is inexpensive. which can be easily installed on thevehicle without any tools by the owner. and which does not affect theoperation of the original circuitry associated with the headlights ofthe vehicle. Moreover. the invention can be easily installed on thevehicle even after the original manufacture thereof without affectingthe operation of the existing circuitry of the vehicle.

The apparatus of the invention includes transister means which isconnected to the existing fuse block of the vehicle and to the existinglight dimmer switch of the vehicle. The output of the transister isconnected to a buzzer unit so that the buzzer unit is activated when theheadlights are turned on but the ignition is off.

These and other features and advantages of the in vention disclosedherein will become more fully understood upon consideration of thefollowing specification and accompanying drawings wherein likecharacters of reference designate corresponding parts throughout theseveral views and in which:

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an electrical schematicdiagram illustrating one embodiment of the invention;

FIG. 2 is an electrical schematic diagram illustrating an alternateembodiment of the invention;

FIG. 3 is an exploded perspective view illustrating the connection ofthe invention to the existing fuse block of a vehicle;

FIG. 4 is a partial end view of the fuse block connection of FIG. 3;

FIG. 5 is an exploded perspective view illustrating the connection ofthe invention to the existing light dimmer switch of a vehicle; and,

FIG. 6 is an exploded perspective view illustrating the connection ofthe invention to an existing buzzer unit of a vehicle.

These figures and the following detailed description disclose specificembodiments of the invention, however. the inventive concept is notlimited thereto since it may be embodied in other forms.

DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS Referring to thedrawings. it will be seen that the invention makes use of the existingfuse block F and headlight dimmer switch D of a vehicle. Also. it willbe noted that use may be made of an existing buzzer unit U if it isavailable in the vehicle.

Referring now to FIG. I which illustrates schematically the firstembodiment of the invention, the warning unit 10 includes generally atransistor Q, having its emitter E connected to the foot operatedheadlight dimmer switch D. its base B connected to the fuse block Fthrough a resistor R,. and its collector C connected to a buzzer unit U,as will become more apparent. The transistor 0, is of the pnp type whichconducts when the potential at its emitter E is a predetermined amount(usually 0.2416 volt) greater than the potential at its base B. The baseB is connected to that portion of the fuse block F which is powered fromthe existing vehicle battery BT through the existing ingition switch Iof the vehicle. Thus. when the ignition switch I is closed. thepotential at the base B of transistor 0, is equal to that of the batteryBT but when the ignition switch I is open, no voltage is supplied tobase B. The emitter E of transistor O, is connected to the dimmer switchD so that voltage is supplied to the emitter E when the existingheadlight switch H is closed but not when it is open. The collector C oftransistor 0, is connected directly to the hot side of the buzzer unitU, while the ground side of unit U, is connected directly to ground.normally the metal body of the vehicle.

A bias resistor R is connected between the common point between resistorR, and the fuse block F and ground, again normally the metal body of thevehicle. The resistor R, is used as a current limiting device to preventdamage to the transistor Q, when the headlights are powered but theignition switch I is open as will become more apparent. The biasresistor R is used to provide the necessary bias to make transistor 0,conduct and is sufficiently large to prevent excess power drain frombattery BT when the ignition switch I is closed.

Referring now to FIGS. 3 and 4, a representative existing fuse block Fis illustrated. The block F includes a mounting base 12,- onto which aseries of pairs of spring contacts t-,- are positioned. One contactc',--l of each pair is connected to the vehicle battery BF through theignition switch I via a common bus B,.-. Fuses f,- are slipped intoposition between the contacts 0, to fuse equipment E, individuallyconnected to the other contacts C -Z. This allows the equipment E to beoperated only while the ignition switch I is closed.

The wire w, seen in FIG. I connected to resistors R, and R. is connectedto any of the contacts C F that are connected to the battery BF by theignition switch I. An adapter 11 is provided on the end of wire w, foruse in connecting same to the contact C The adapter I l is a thin stripof electrically conductive material such as brass which can be easilybent partly around the contact on the fuse f and the fuse fp with theadapter 11 slipped back into position between a pair of the contacts c,as seen in FIG. 4 without interfering with the operation of theequipment E,. powered through the fuse f This causes a voltage to beapplied to the base B of transistor 0, when the ignition switch I isclosed.

Referring to FIG. 5, a representative existing, footoperated dimmerswitch D is illustrated. Switch D has three blade type terminals I I andThe middle terminal I, is normally the common terminal which isconnected to the battery BT through the headlight switch H. The sideterminals 1 and 1;, are normally connected to the high and low beaminputs respectively of the headlights L. Switch D is effective in afirst condition to connect terminal I with terminal 1 and effective in asecond condition to connect terminal I, with terminal The wire w; seenin FIG. I connected to the emitter E of transistor Q is connected to thecommon terminal of dimmer switch D. A connector 12 is provided on theend of wire W2 for use in connecting same to the terminal 1,. Theconnector 12 is a resilient plate of a conducting material such as brassthat has been slit at [4 in a first direction and cross-slotted at 15 oneach end of the slit l4 to form a pair of resilient tongues 16. Theconnector 12 is positioned on the common terminal r, of switch D byforcing the terminal I, through slit 14. The resiliency of tongues 16 issuch that the connector 12 will be held on terminal and the terminalsr,r;, can be reinserted in the existing terminal block TB without theconnector 12 interfering with the operation thereof.

The buzzer unit U is of known construction that is electrically operatedto produce an audible warning signal. If a buzzer unit U is alreadyavailable on the vehicle and has its hot side connected to the vehiclebut tcry BT through an appropriate signal switch SW usu ally forming apart of the ignition switch as shown by phantom lines in FIG. 1, then,the buzzer unit U, can be eliminated and the collector C of transistor Tconnected directly to the hot side of buzzer unit U. Of course, theground side of buzzer unit U is connected to ground.

Referring to FIG. 6, a representative existing buzzer unit U isillustrated. The particular unit U is combined with the horn relay HR.however. the operation of horn relay HR is completely independent of thebuzzer unit U. Therefore, only the buzzer unit U will be discussed. Theunit U illustrated is grounded to the vehicle body through the case 11,.and has a hot terminal n, which is connected to the battery BT throughthe switch SW. The connection of the collector C of transistor O toterminal u is made by wire w to which a connector 12 is attached. Theconnector 12 is positioned onto terminal u, in the same manner as thatdescribed for dimmer switch D and the buzzer unit U replaced in itsconnector block CB without interfering with the operation thereof.

In operation. it will be seen that when the ignition switch 1 is closed,voltage is applied to the base B of transistor 0.. When the headlightswitch H is closed, voltage is applied to the emitter E of transistorQ,. Because transistor Q, will only conduct when the voltage at emitterE is high and the voltage at base B is low, transistor Q will notconduct to energize buzzer unit U or U when the ignition switch I isclosed. Further, transistor Q will not conduct when the headlight switchH is open. When headlight switch H is closed and ignition switch I isopen, transistor Q will conduct to energize buzzer unit U or U toproduce the desired audible signal to prevent the headlights from beingadvertently left in an on" position.

While the values of the components may be changed, the followingcomponents operate satisfactorily.

Component Identification Transistor 0. MP5 6562 (Motorola) Resistor R lKohm Resistor R lK ohm Buzzer Unit U Archer Cat. No.

A second embodiment of the invention is illustrated in FIG. 2 and isdesignated generally by the numeral 110. The unit 110 is adapted for usewith vehicles which have an existing buzzer unit U that has its hot sideconnected directly to the battery BT and its ground side groundedthrough the signal switch SW. Of course, the vehicle has the ignitionswitch I, the dimmer switch D, headlight switch H, headlights L, andfuse block F.

Unit 110 includes a pnp transistor 0 with its base B connected throughresistor R to the ignition switch activated contacts c on fuse block Fas disclosed for unit 10. The emitter E of transistor O is connected tothe common hot terminal r of dimmer switch D as disclosed for unit 10. Aresistor R is connected between the common point between resistor R andfuse block F and ground, usually the metal body of the vehicle. An npntransistor 0 has its base B connected to the collector C of transistor0.; through a resistor R and its emitter E connected to ground. Thecollector C,, of transistor 0;, is Connected to the ground side ofbuzzer unit U The buzzer unit U is similar to the unit U illustratedexcept that it also has a grounded terminal 14,, in addition to its hotterminal 11,. The connector 12 is used to connect the collector C to thegrounded terminal u, rather than the hot terminal a,

The transistor Q like transistor Q conducts when the voltage at itsemitter E is high and the voltage at its base B is low. Transistor Q,,on the other hand, conducts when the voltage at its collector C is highand the voltage at its base 8,, is also high. Thus, transistor Q willconduct to make the voltage at base B high only when the headlightswitch H is closed and the ignition switch 1 is open. Since the voltageat the collector C; of transistor 0 is always high, transistor Q, willconduct when transistor Q conducts to connect the ground side of buzzerunit U to ground to energize same and produce the desired audiblewarning signal.

The resistor R is used as a current limiting device to prevent damage totransistor 0 when the headlights are powered but the ignition switch Iis open. The resistor R is used to provide the necessary bias to maketransistor Q conduct and is sufficiently large to prevent excess powerdrain from battery BT when the ignition switch I is closed. The resistorR is used to limit the current flowing through transistor Q and toprovide the necessary bias to cause transistor 0;, to conduct whentransistor 0 is conducting.

While the values of the components may be changed. the followingcomponents operate satisfactorily.

Component Identification Transistor 0, MP5 6562 (Motorola) -ContinuedComponent Identification Transistor Qa MP (M (Motorola) Resistor R- l Kohm Resistor R l k ohm Resistor R 13 K ohm Because the fuse block F ispowered when the ignition switch I is in its ON" position and in itsACCES- SORY" position, the accessory position can be used if it isdesirable to leave the headlights on but the ignition off without thebuzzer unit U, U or U; sounding. Also, on some vehicles, some of thecontacts c,.- of the fuse block F are always powered while the rest ofthe contacts are connected to the vehicle battery through the ignitionswitch I. A simple way to check to see if the adapter ll is connected tothose contacts controlled by switch I is to install the adapter ll andunit 10 or [10, close the headlight switch H, and open the switch I. Ifthe buzzer unit U, U or U sounds, the connection is correct. If thebuzzer unit does not sound, then the adapter 11 can be changed to othercontacts on the fuse block F until the buzzer sounds.

It is to be understood that full use may be made of modifications,substitutions and equivalents without departing from the scope of theinvention disclosed herein.

1 claim:

1. A headlight warning apparatus for use on a vehicle having a firstcircuit controlled by an ignition switch and a headlight switch forcontrolling the operation of the headlights through a second circuitindependently of the ignition switch comprising:

signal means having a hot terminal and a ground terminal directlyelectrically grounded for generating a warning signal upon receipt of anelectrical volt age at said hot terminal; and,

a control means having a first input; a second input;

and an output. said first input operatively connected to the firstcircuit so as to have voltage supplied thereto only when the ignitionswitch is closed; said second input operatively connected to the secondcircuit so as to have voltage supplied thereto only when the headlightswitch is closed, and said output operatively connected to said hotterminal on said signal means; said control means constructed andarranged to cause the voltage imposed on said second input to be imposedon said output only when voltage is not supplied to said first input sothat voltage will be supplied to said hot terminal of said signal meansto generate a warning signal only when said headlight switch is closedto supply voltage to said second input and said ignition switch is opento not supply voltage to said first input.

2. The headlight warning apparatus of claim 1 wherein the first circuitincludes a fuse block having at least one pair of spring contactspowered through the ignition switch and a fuse connecting the pair ofcontacts; wherein the second circuit includes a dimmer switch forcontrolling the output of the headlights having a common blade terminalpowered through the headlight switch; and wherein said system furthercomprises an adapter electrically connected to said base of saidtransistor, said adapter including a thin strip of electricallyconductive material bendable around said Ill fuse and positionablebetween said fuse and one of said contacts while electrically connectingsaid contact with said fuse and said base; and, a connector electricallyconnected to the emitter of said transistor. said connec tor including aresilient plate defining a terminal receiving slit therein and includinga resilient tongue on opposite sides of said slit. said slit adapted toslidably receive said blade terminal thcrethrough and said tonguesadapted to maintain said connector onto said terminal.

3. A headlight warning apparatus for use on a vehicle having a firstcircuit controlled by an ignition switch and a headlight switch forcontrolling the operation of the headlights through a second circuitindependently of the ignition switch comprising:

signal means for generating a warning signal when an electrical voltageis imposed there-across;

a pnp type transistor having a base. an emitter, and collector, saidemitter electrically connected to said second circuit so that voltage issupplied thereto when the headlight switch is closed and said collectorconnected to said signal means;

a first resistor connecting said base of said transistor to said firstcircuit so that voltage is supplied to said base through said firstresistor when the ignition switch is closed; and.

a second resistor connecting the common point between said firstresistor and said first circuit to electrical ground so that saidemitter is electrically connected to said collector only when theignition switch is open to cause a voltage to be imposed across saidsignal means if the headlight switch is closed.

4. A headlight warning apparatus for use on a vehicle having a firstcircuit selectively connected to a voltage source by an ignition switchand a headlight switch for selectively connecting the headlight to thevoltage source through a second circuit independently of the ignitionswitch comprising:

signal means having a hot terminal electrically connected to the voltagesource and a ground terminal for generating a warning signal when saidground terminal is electrically grounded;

a first pnp type transistor having a first base, a first emitter, and afirst collector, said emitter electrically connected to said secondcircuit so that voltage is supplied thereto when the headlight switch isclosed;

a second npn type transistor having a second base. a second emitter. anda second collector, said second emitter electrically grounded and saidsecond collector electrically connected to said ground terminal of saidsignal means;

a first resistor electrically connecting said first base of said firsttransistor to said first circuit so that voltage is supplied to saidfirst base through said first resistor when said ignition switch isclosed;

a second resistor connecting the common point between said firstresistor and said first circuit to electrical ground; third resistorelectrically connecting said second base of said second transistor tosaid first collector of said first transistor so that said firsttransistor conducts only when the ignition switch is open to cause saidsecond transistor to conduct if the headlight switch is closed toconnect said ground terminal of said signal means to electrical ground.

1. A headlight warning apparatus for use on a vehicle having a firstcircuit controlled by an ignition switch and a headlight switch forcontrolling the operation of the headlights through a second circuitindependently of the ignition switch comprising: signal means having ahot terminal and a ground terminal directly electrically grounded forgenerating a warning signal upon receipt of an electrical voltage atsaid hot terminal; and, a control means having a first input; a secondinput; and an output, said first input operatively connected to thefirst circuit so as to have voltage supplied thereto only when theignition switch is closed; said second input operatively connected tothe second circuit so as to have voltage supplied thereto only when theheadlight switch is closed, and said output operatively connected tosaid hot terminal on said signal means; said control means constructedand arranged to cause the voltage imposed on said second input to beimposed on said output only when voltage is not supplied to said firstinput so that voltage will be supplied to said hot terminal of saidsignal means to generate a warning signal only when said headlightswitch is closed to supply voltage to said second input and saidignition switch is open to not supply voltage to said first input. 2.The headlight warning apparatus of claim 1 wherein the first circuitincludes a fuse block having at least one pair of spring contactspowered through the ignition switch and a fuse connecting the pair ofcontacts; wherein the second circuit includes a dimmer switch forcontrolling the output of the headlights having a common blade terminalpowered through the headlight switch; and wherein said system furthercomprises an adapter electrically connected to said base of saidtransistor, said adapter including a thin strip of electricallyconductive material bendable around said fuse and positionable betweensaid fuse and one of said contacts while electrically connecting saidcontact with said fuse and said base; and, a connector electricallyconnected to the emitter of said transistor, said connector including aresilient plate defining a terminal receiving slit therein and includinga resilient tongue on opposite sides of said slit, said slit adapted toslidably receive said blade terminal therethrough and said tonguesadapted to maintain said connector onto said terminal.
 3. A headlightwarning apparatus for use on a vehicle having a first circuit controlledby an ignition switch and a headlight switch for controlling theoperation of the headlights through a second circuit independently ofthe ignition switch comprising: signal means for generating a warningsignal when an electrical voltage is imposed thereacross; a pnp typetransistor having a base, an emitter, and collector, said emitterelectrically connected to said second circuit so that voltage issupplied thereto when the headlight switch is closed and said collectorconnected to said signal means; a first resistor connecting said base ofsaid transistor to said first circuit so that voltage is supplied tosaid base through said first resistor when the ignition switch isclosed; and, a second resistor connecting the common point between saidfirst resistor and said first circuit to electrical ground so that saidemitter is electrically connected to said collector only when theignition switch is open to cause a voltage to be imposed across saidsignal means if the headlight switch is closed.
 4. A headlight warningapparatus for use on a vehicle having a first circuit selectivelyconnected to a voltage source by an ignition switch and a headlightswitch for selectively connecting the headlight to the voltage sourcethrough a second circuit independently of the ignition switchcomprising: signal means having a hot terminal electrically connected tothe voltage source and a ground terminal for generating a warning signalwhen said ground terminal is electrically grounded; a first pnp typetransistor having a first base, a first emitter, and a first collector,said emitter electrically connected to said second circuit so thatvoltage is supplied thereto when the headlight switch is closed; asecond npn type transistor having a second base, a second emitter, and asecond collector, said second emitter electrically grounded and saidsecond collector electrically connected to said ground terminal of saidsignal means; a first resistor electrically connecting said first baseof said first transistor to said first circuit so that voltage issupplied to said first base through said first resistor when saidignition switch is closed; a second resistor connecting the common pointbetween said first resistor and said first circuit to electrical ground;a third resistor electrically connecting said second base of said secondtransistor to said first collector of said first transistor so that saidfirst transistor conducts only when the ignition switch is open to causesaid second transistor to conduct if the headlight switch is closed toconnect said ground terminal of said signal means to electrical ground.